- Male reproductive system
- Lymphatic system
- Skeletal system
- Head muscles
- Neck muscles
- Muscles of upper limb
- Muscles of pectoral girdle
- Muscles of shoulder region
- Muscles of upper arm
- Muscles of forearm
- Muscles of hand
- Thoracic muscles
- Muscles of back
- Muscles of lower limb
- Blood vessels
- Respiratory system
- Digestive system
- Endocrine glands
- Nervous system
- Female reproductive system
Flexor pollicis longus
The flexor pollicis longus (Latin: musculus flexor pollicis longus) is a long muscle of the upper limb that stretches between the radius and the distal phalanx of the thumb. It is one of the deep muscles of the forearm that is located in the anterior compartment. Together with the flexor digitorum profundus, this deep flexor of the forearm lies in the third muscle layer.
|Flexor pollicis longus|
|Origin||Anterior surface of radius, interosseous membrane of forearm|
|Insertion||Base of distal phalanx of the thumb|
|Action||Flexion of thumb, flexion of phalanges at first metacarpophalangeal and interphalangeal joints, flexion of wrist|
|Innervation||Anterior interosseous branch of median nerve (C7, C8)|
|Blood supply||Anterior interosseous and radial arteries|
The flexor pollicis longus muscle originates from the proximal anterior surface of the radius and interosseous membrane of the forearm.
Distal fibers of the flexor pollicis longus form a flattened tendon that reaches the thumb via the carpal tunnel. The tendon of the muscle inserts on the base of the distal phalanx of the thumb.
The flexor pollicis longus muscle provides the flexion of the thumb and flexion of the phalanges at the metacarpophalangeal and interphalangeal joints of the first finger. Also, it assists in the flexion of the wrist at the wrist joint.
The flexor pollicis longus is innervated by the anterior interosseous branch of the median nerve (C7, C8).
The medial aspect of the flexor pollicis longus muscle receives arterial blood supply from the anterior interosseous artery that arises from the common interosseous artery. The lateral part of the muscle is supplied by the radial artery - a branch of the brachial artery.